Plaster board



Feb. 5, 1929.

M. K. ARMSTRONG PLASTER BOARD Filed July 12', 1919 Patented Feb.- 5, 1929.

.UNITED STATES 1,701,291 PATENT OFFICE.

MORGAN K. ARMSTRONG, OF WINNETKA, ILLINOIS, ASSIGNVOR, BY MESNE ASSIGN- MENTS, TO UNITED STATES G YPSUM COMPANY.

BLASTER BOARD.

This invention relates to impro-vements 1n plaster boards and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The present application is a continuing application as to common subject-matter disclosedin the two cases and claimed herein, of my Patent No. 1,348,387.

The term plaster board is used herein generically, although the specific kind', of board is more technically known in the 'art -as wall board, which is a board to be applied directly to .the studding and to take the place of both, lath and plaster in the finishing of interior walls.

The board consists generally of top and bottom covering sheets of paper or. other iibrous material, preferably a manila paper, either fully or partially sized, and of an intermediate layer consisting of a plaster body to which the said covering sheets are adhered,

Such boards of the kind heretofore produced, have been made either with the edges of the plaster body exposed at the edges of the covering sheets, which are of like widths, or with the one covering sheet made wider than the other sheet and with the projecting marginal parts of the first sheet turned over upon itself to enclose the edges of the plaster body, and with the second sheet overlapped upon and cemented to the turned-over marginal parts of the other sheet, thus binding the edges of the board.

Board of both kinds has been made by means of a continuous process in which the plastic mix for the body is applied to an advancing bottom sheet and the top sheet is applied and the plastic mixis spread to the desired thickness by passing the board forming material between rolls,-the marrinal portions of the bottom sheet inithe case of the bound edge board, havingbeen turned over by suitable folders, prior to its reaching' the spreading rolls.

While superior to the unbound board, the bound edge board lastmentioned has several disadvantages. One of the chief of these is due to the fact that the top sheet is apt to he insccurely cemented at its edges to the turned-over marginal parts of the bottom sheet, so that said edges curl or stand away from the body of the bo'ard and arev apt to.'

be torn or broken away, thus greatly reducing the strength of the boardat its edges.

The object of the invention is to produce a board wherein the edges of the top sheet are enclosed, and in which the edge itself is so reinforced as to reduce to a minimum, the possibility of breaking the edges of the board. l

Other advantages of the board will be pointed out as I proceed with my specification.

In the drawings:

Figure l illustrates a perspective view of a piece of plaster board, embodying my invention.

Figure 2 illustrates, on an enlarged scale, a transverse section through the improved plaster board.

Figure 3 illustrates a cross section through the adjoining margins of two pieces of plaster board nailed to an upright studding.

Referring now in detail to that embodiment of the invention illustrated in the accompanying drawings :-5, and 6 indicate respectively, the top and bottom sheets or coverings of fibrous material such as paper, andl 7 indicates the plaster body of 'suitable thickness between and enveloped by said top and bottom sheetsor coverings.

The bottom sheet 6 is made of a strip of paper of a width greater than that of the top sheet 5, and the margins 6l of said 'sheet 6 are turned over upon and in overlapping relation withthe margins 5a of the top sheet 5, which is depressed into the plaster body. In the manufacture of said plaster board, plaster is permitted to How upon the surface ofthe-margins (5a-and during the turningover of said margins, the plaster'thereon engages the top surfaces of the margins 58, so as to provide an adhesive layer of plaster 7 between said margins. lThe plaster layer 7EL which forms a continuation of the main plaster body, securely aiiixes or cements the turned-over margins 6a of the bottom sheet to the depressed margins 5a of the top sheet, so that a rounded, bound edge is provided for the board, with the edges of the margins 6 facing towards the median line thereof.

The margins of the board are tapered or beveled away from the plane of the face of the board provided by the sheet 6, towards the rounded edge, as clearly shown by comparison of said edges with the lateral prolongations of said face, indicated by the dotted lines `8'"in Figure 2. This taperedofli' formation is advantageous for the following reason.

When applying the board to a studding 9,

, as shown in Fig. 3, the edges of adjoining boards are spaced equally on each side of the center of said studding, with that side of the boards formed by the top sheets 5 placed against the studding. `This brings the sides of the boards formed by the sheets 6 outermost, so that they may be finished off 1n. the desired manner. Nails 10 are driven through the margins of the board sections, each nail passing throughl the plaster body 7, plaster layer paper coverings, that is to say, the sheet 6 at the beveled margins, the depressed, enclosed margins 5a of the sheet 5, and the; turnedover margins 6a of the sheet 6, which margins 6a engage against the studdmg. After the nails have been thus driven in, a joint or seam liller in the form of a suitable plastic material, 11, is applied to fill up the space between the adjacent rounded edges of the boards, and over the adjacent beveled or tapered-olf margins thereof, and the filler is then leveled off so that its outer surface is flush with the exposed surfaces of the sheets 6 of the boards. A part of this filler will also get behind the rounded edges of the boards and form a head 11a which, when the filler has hard/cned, will act as a key or locking means, preventing the filler from falling out of place. This filler, when it has been leveled oii', will also cover up the nail heads, so that they will not be visible in the finished wall.

The bevelling of the margins of the sections may be produced by a modification of the machine shown in my Patent No. 1,- 348,387, by giving a slight inclination to the edges of the conveyor belt 15 on which the plaster board is carried.

Other advantages of the improved plaster board will be manifest to those familiar with the art. It will be noted that no edges of either sheet of paper forming the board are exposed outwardly towards the edges of the board. The edges of the marginal parts 6a of the bottom or outer sheet, are turned inwardly and securely cemented, and there is no danger of their being dislodged or detached in the handling of the board, the rounded edges of which are perfectly bound, without any free edge of paper near thereto to be torn or broken away in the handling of the board.

i The marginal parts 5a of the top or inner sheet, are not only depressed below the overlapping marginal parts 6EL of the bottom fsheet to such an extent as to provide ya suflicient body of plaster to securely and effivciently attach them together and make both marginal parts thus a component part of the board, but in addition, the said marginal 7, and three thicknesses of' meneer parts of the top sheet act by their tensile strength to reinforce the marginal parts of the vboard and to strengthen the same at its edges.

In the making of the board, the sheets are preferably sohlvproportioned that the marginal parts of the top sheet approach as nearly as may be, the edges of the board, thus not only iving all the reinforcement to thel edges ofg .the board that may be obtained by this construction, but also insuring three thicknesses of paper adjacent the edge of the board, to be engaged when nailing the board in place.

Another feature of the board which is important is the" fact that the plaster at the edges of the board always completely fills the rounded fold or bend of the marginal i sheet when said parts are brought into overlapping engagement with the marginal parts of the top sheet.

While in describing the board, I have referred to paper as the preferred coverings 'for the plaster body, it will be understood that the invention is not limited threto, as sheets or strips of any material adapted to the purpose may be used, and I, therefore, in the claims, refer to the sheets enclosing the plaster body of the board, as a fibrous material.

I claim as my invention:

1. A plaster board comprising a plaster body and top and bottom sheets of fibrous material adhered to and forming a covering for said plaster body, said bottom sheet being wider than the top sheet and having its margins turned over and inwardly so as to lap the margins of the top sheet, the marginal parts of the board being tapered or beveled on one side thereof.

2. A plaster board comprising a plaster body and opposed sheets 'of fibrous material adheringto and forming a covering for said plaster ody, one of said sheets being wider than the opposed sheetand inclosing the edges of the plaster body and overlapping the marginal parts of the other sheet, the said other sheet having its marginal parts depressed below said overlapping marginal parts of the opposed sheet with a substantial plaster layer interposed between the adjacent parts ofthe overlapping and underlapping marginal parts of said sheets.

3.In a plaster board, a body made of plastic material, theff 'f being parallel for a distance crosswise of the board, thence tapered to the edges, the edges rounded and the whole enveloped in a folded sheet of enveloping material.

material adhering to one face of the body.

and extending to adjacent one -edge of the body, covering sheet adhering to the other face of the body and having an extension at one side folded over to inclose the edge of the body and overlie a portion of the body and the edge portion of the first covering sheet.

6. A plaster board comprising a body, a relatively stiff imperforate covering sheet of fibrous material adhering to one face of the body and extending to adjacent one edge of the body, and a second covering sheet adhering to-the other face of the body and having an extension at one side folded over to inclose the edge of the body and overlie a vportion of the body and the edge. portion of the first covering sheet. j

7 A plaster board comprising ya body, an

imperforate covering sheet adhering to oneface of the body and extending to adjacent one edge of the body, and a secondcovering sheet adhering to the other face ofthe body` and having an extension at one side folded over `to inclose the edge of the body\and`over lie a portion of the body and the edge por-4 tion of the first covering sheet.

8. A plaster board compr1s1ng a body, an

iniperforate covering sheet adhering to one. face of the body and extending to adjacentone edge of the body', and a second imperforate covering sheet adhering to the other face of the body and having an extension at.

one side folded over to inclose the edge of the body` and overlie a portion` of the body and the edge portion ofthe rst covering sheet.

9. A plaster board comprising'a body, a

relatively stiff imperforate covermgsheet of' fibrous material adhering to one face of the body and extending to adjacent one edge of the body, .and a second relatively stiff imperforate covering `sheet yadhering to the other face of the bodvand having an extension at 'one side folded over to inclose the edge of the body and overlie a portion of the body and the edge portion of the first covering sheet. l

10. A plaster board comprising in combinationa board-like body of plaster or the and a second similarly relatively stiA i like body of ve.op1ng like which is thinner near the edges than the body of the board,`"ard covering material enveloping the edges of said board and adhering to the plaster body. f

11. A plaster board comprising in combination a board-like bodyof plaster or the like which is gradually reduced in thickness near the edges thereof, and covering matcrial enveloping the edges of said board and adhering to the plaster body.

12.v A plaster board comprising in combination a board-like body of plaster or the like, having enveloping covering material over the face side and edges thereof., said board being beveled a distance in from the edges, whereby the face side of the board near the beveled portions lies below the plane -of the face surface.

13. A plaster board comprising in combination a board-like body of plaster or the like, having enveloping covering material over the face side and edges thereof, said board being .beveled a distance in from the edges to position the face surface of the beveled portion below the plane of the face surface of the board, and the opposite face of the board being also slightly beveled at the edges thereof, whereby wlien a pair of boards is laced edge to edge a rdepression is'formed or receiving plaster or the like to cover and conceal the joint between the` boards. y y

14. A plaster board comprising a boardplaster or the like, the side edges of which are substantially rounded and covered with protectingcovering mate- .,rial adhering thereto, the curvature of said edges being such as to provide a depression of substantial width between adjacent boards placed edge to edge to receive material for concealing the joint and providing,

continuity of surface between adjacent boards. fr I 15. In a wall or analogous structure, the combination comprising a plurality lof wall boards placed edge to edge, each consisting of'a board-like body of plaster having encovering material adhering thereto and having the edges thereof smoothly reduced in thickness to provide depressions of substantial. width between adjacent j boards, supports for the edges of said boards and a plastic joint filler placed in said depressions and formed flush with the outer surface of said boards to conceal the joints and provide continuity of wall surace.

loo

` 16. In a wall or analogous structure, the

combination comprising a plurality of wall -boaids placed edge to edge, each consistingof a board-like body of plaster having en-l veloping covering material adhering'thereto and having the edges thereof smoothly tapered to provide depressions of substantial width Aand of gradually increasing depth, supports for the edges of said boards, and a plastic joint filler placed in said depressions `and formed flush Ywith the outer surface of said boards to conceal the joints and provide continuity of wall surface, the rear edges of said boards being slightly rounded to rovide enlarged pockets at the back of the oards to receive a quantity of' sheets and filling; and a layer of fibrous material bonding to the plastic body of the board interposed between the plastic body and filler to reinforce them mutually.

18.` A method of erecting a wall which is characterized by forming plaster sheets having respective depressed margins covered with a layer of fibrous material such as paper; nailing -the said plaster sheets to the wall studding with the depressed margins ladjacent each other; and supplying a filler to the adjacent depressed covered margins so that the fibrous covering shall be interposed between the filler and th'hplaster sheet whereby said fibrous covering reinforces the filler as well as the plaster sheet margin and serves to bond them together.

19. A method of erecting a wall which is characterized by forming plaster sheets having respective depressed margins; a covering sheet of fibrous material to each` plaster sheet including its depressed margin; causing the plaster sheets to set; nailing the covered set plaster sheets to studding to Aform a wall with their depressed margins adjacent each other; and applying a plastic filler tothe covered depressed margins to produce a continuous plane surface of the covered areas of the plaster sheets and the filler; and permitting the plastic filler to set.

20. A method of erecting a wall comprising the securing of plaster or the like, having smooth beveled edges, with their beveled edges adjacent and forming a more or lessl tapered depression between the adjacent sheets, the means for securing the board being placed within the said depression; and introducing a filling material in said depression to bridgethe interval between the adjacent sheets and to conceal said fastening means.

21. A method of erecting a wall comprising the placing edgeI to edge lsheets of plaster board or the like having exposed surfaces in substantially the same plane .but having depressed adjacent areas protected by fibrous covering material; and applying filling material to the depression so that the exposed surfaces of the filling material shall merge with-the exposed surfaces of the sheets.

22. A manufactured wall board sheet having two parallel surfaces in its two greatest dimensions and a surface at the edge of the board, the surface at the edge of the board having a slanting relation to the parallel surfaces and means for holding a plastic material on the slanting surface to form a continuous surface between the adjacent edges of the exposed surfaces of adjacent boards when in place.

23. A manufactured wall board sheet having two parallel surfaces in its two greatest dimensions anda surface at the edge of board having a slanting relation to the parallel surfaces and an undercut portion adjacent the slanting surface for holding a plastic material on the slanting surface to form continuous `surface between 'the adjacent edges of ,the exposed surfaces of adjacent boards when in place.

24. In combination, the frame of a house,

manufactured wall board sheets extending between portions of the frame and having edges extending along portions of the frame, the wall board sheets having nailing surfaces at the sides of the respective boards and between the planes of the outer and ,inner surfaces and a space adjacent the edges of the nailing surfaces of and between the adjacent edges of adjacent sheets and a hardening plastic means 'for filling the space between adjacent sheets.

25. In combination the frame of a house,

`manufactured wall board sheets extending between portions of the frame and having edges extending along portions of the frame,

the wall board sheets having nailing sur-A faces'at an angle less than a right'angleto the surface next to the frame, and a means for lling the space between the two adjacent edges of adjacent wall board sheets, connecting the outer surfaces thereof and lcovering the nailing surfaces.

26. In combination, thev frame of a house, manufactured wall board Sheetsextending between portions of the frame and having edges extending along portions of the frame, the wall board sheets having surfaces at their edges making acute angles with the respective surfaces adjacent the frame and .between the outer and inner surfaces of the wall board sheets, a hardening plastic means filling the vspace between adjacent sheets, and adjacent edges of adjacent sheets hav- 1n toghold the latter in place.

In testimony that I claim the foregoing as my invention, I affix my @signature this 27th day of June, A. D. 1919.

MORGAN K. ARMSTRONG.

surfaces coacting with the filling means 

